tdata.h

Solaris环境下的数据挖掘算法：birch聚类算法。该算法适用于对大量数据的挖掘。

/*
   ========================================================================
   DEVise Data Visualization Software
   (c) Copyright 1992-1996
   By the DEVise Development Group
   Madison, Wisconsin
   All Rights Reserved.
   ========================================================================

   Under no circumstances is this software to be copied, distributed,
   or altered in any way without prior permission from the DEVise
   Development Group.
   */

/*
   $Id: TData.h,v 1.11 1996/12/03 20:32:09 jussi Exp $

   $Log: TData.h,v $
   Revision 1.11  1996/12/03 20:32:09  jussi
   Improved Init/Get/Done interface.

   Revision 1.10  1996/11/23 21:14:22  jussi
   Removed failing support for variable-sized records.

   Revision 1.9  1996/11/22 20:41:06  flisakow
   Made variants of the TDataAscii classes for sequential access,
   which build no indexes.

   ReadRec() method now returns a status instead of void for every
   class that has the method.

   Revision 1.8  1996/11/12 17:21:24  jussi
   Put back the 'virtual' keyword from the int RecSize() declaration.
   It had somehow disappeared, with the result that GData was never
   cached in memory! In QueryProcFull.c, tdata->RecSize() was supposed
   to return the GData recsize but instead returned zero because the
   method was not declared virtual.

   Revision 1.7  1996/10/04 17:24:15  wenger
   Moved handling of indices from TDataAscii and TDataBinary to new
   FileIndex class.

   Revision 1.6  1996/08/04 21:59:52  beyer
   Added UpdateLinks that allow one view to be told to update by another view.
   Changed TData so that all TData's have a DataSource (for UpdateLinks).
   Changed all of the subclasses of TData to conform.
   A RecFile is now a DataSource.
   Changed the stats buffers in ViewGraph to be DataSources.

   Revision 1.5  1996/07/23 20:13:07  wenger
   Preliminary version of code to save TData (schema(s) and data) to a file.

   Revision 1.4  1996/06/12 14:56:31  wenger
   Added GUI and some code for saving data to templates; added preliminary
   graphical display of TDatas; you now have the option of closing a session
   in template mode without merging the template into the main data catalog;
   removed some unnecessary interdependencies among include files; updated
   the dependencies for Sun, Solaris, and HP; removed never-accessed code in
   ParseAPI.C.

   Revision 1.3  1996/01/13 21:08:47  jussi
   Added copyright notice.

   Revision 1.2  1995/09/05 22:15:45  jussi
   Added CVS header.
   */

/* Textual data virtual base class */

#ifndef TData_h
#define TData_h

#include "DeviseTypes.h"
#include "RecId.h"
#include "DataSource.h"

// A simple Status for TData
enum TD_Status {
    TD_OK = 0,
    TD_EOF,
    TD_FAIL
};

class AttrList;

class ReleaseMemoryCallback {
  public:
    virtual void ReleaseMemory(MemMgr::PageType type,
                               char *buf, int pages) = 0;
};

class TDataRequest {
  public:
    Boolean IsDirectIO() { return (iohandle == 0); }

    RecId nextId;                       // next record to return in GetRecs()
    RecId endId;                        // where current GetRecs() should end
    ReleaseMemoryCallback *relcb;       // callback to release pipe memory
    int iohandle;                       // handle for data source I/O

    char *lastChunk;                    // beginning of unused pipe data chunk
    char *lastOrigChunk;                // beginning of pipe data chunk
    int lastChunkBytes;                 // size of pipe data chunk
};

class TData {
  public:

    // creates a new data source based upon the parameters
    TData(char* name, char* type, char* param, int recSize);

    // uses an existing data source
    TData(DataSource* data_source = NULL);

    virtual ~TData();

    /**** MetaData about TData ****/
    /* Return attribute info */
    virtual AttrList *GetAttrList() = 0;

    /* Return # of dimensions and the size of each dimension,
       or -1 if unknown */
    virtual int Dimensions(int *sizeDimension) = 0;

    /* Return record size, or -1 if variable record size */
    virtual int RecSize() { return _recSize; }

    /* Return page size of TData, or -1 if no paging structure */
    virtual int PageSize() { return -1; }

    /* Return true if TData deletes records from the beginning
       due to limited disk/memory buffer. */
    virtual Boolean HasDeletion() { return false; }

    /* Return true if TData appends records */
    virtual Boolean HasAppend() { return false; }

    /* Use this to get user defined attributes.
       We reserve attributes 0-SysAttrNum for internal use.
       A -1 is returned for none-existing attrNum*/
    virtual int UserAttr(int attrNum){ return -1; }

    // if the data source is not ok or it has changed versions,
    // then DataSourceChanged will be called.
    // returns false if there is a problem with the data source
    void CheckDataSource() {
	if( !_data->IsOk() || _data->Version() != _version ) {
	    InvalidateTData();
	}
    }

    // The data source that this tdata is defined upon has changed.
    // The tdata should clean in-memory structures like indicies, etc.
    // The derived method should also be sure to call this one which
    // cleans the query processor
    virtual void InvalidateTData();

    /* Get name */
    char *GetName() { return _name; }

    /* convert RecId into index */
    virtual void GetIndex(RecId id, int *&indices) = 0;

    virtual Boolean WriteIndex(int fd) { return false; }
    virtual Boolean ReadIndex(int fd) { return false; }

    /**** Getting record Id's ****/

    /* Get RecId of 1st available record, return true if available */
    virtual Boolean HeadID(RecId &recId) = 0;

    /* Get RecId of last record, return true if available */
    virtual Boolean LastID(RecId &recId) = 0;

    /**** Getting Records ****/

    typedef TDataRequest *TDHandle;

    /**************************************************************
      Init getting records.
    ***************************************************************/
    virtual TDHandle InitGetRecs(RecId lowId, RecId highId,
                                 Boolean asyncAllowed = false,
                                 ReleaseMemoryCallback *callback = NULL) = 0;

    /**************************************************************
      Get next batch of records, as much as fits into buffer. 
      Return false if no more.
      input:
      buf: where to start putting records.
      bufSize: size of buffer being supplied.
      output:
      startRid : starting record ID of this batch 
      numRecs: number of records.
      dataSize: # of bytes taken up by data.
      **************************************************************/
    virtual Boolean GetRecs(TDHandle handle, void *buf, int bufSize,
                            RecId &startRid, int &numRecs, int &dataSize) = 0;

    virtual void DoneGetRecs(TDHandle handle) = 0;

    /* For writing records. Default: not implemented. */
    virtual void WriteRecs(RecId startId, int numRecs, void *buf);

    /* get the time file is modified. We only require that
       files modified later has time > files modified earlier. */
    virtual int GetModTime() = 0;

    /* Do a checkpoint */
    virtual void Checkpoint() = 0;

    /* Save the TData to a TData file. */
    DevStatus Save(char *filename);

    DataSource* GetDataSource() { return _data; }

  protected:

    char *_name;                        // name of data stream
    char *_type;                        // type of data stream
    char *_param;                       // parameters of data stream
    int _recSize;                       // size of record

    DataSource* _data;                  // data source
    int _version;                       // last _data->Version()

    char* MakeCacheFileName(char *name, char *type);
    
  private:

    DevStatus WriteHeader(int fd);
    DevStatus WriteLogSchema(int fd);
    DevStatus WritePhysSchema(int fd);
    DevStatus WriteData(int fd);

};

#endif